1. Field of the Invention
This invention relates generally to instruction and analyzing aids, and particularly to football play analyzing and teaching devices. 2. Description of the Prior Art
It is generally known to use devices and symbols on a regulation football field, and the like, to assist coaches in instructing their players. U.S. Pat. No. 1,538,203, issued May 19, 1925, to C. B. Moran, shows the use of wire-guided dummies for this purpose, while U.S. Pat. No. 2,458,984, issued Jan. 11, 1949, to C. A. Engle, discloses the use of a strip placeable on a playing field to show the position of the offensive linemen during practice of the offensive backs. In the former, however, the players cannot be in position on the field while the dummies are in place, and in the latter, only the offensive backs are on the field running through plays.
It is also known to use simulated playing fields, usually of tabletop size, to diagram football plays. Examples of these educational devices and amusements are found in U.S. Pat. Nos. 1,927,695, issued Sept. 19 1933, to L. P. Andreas; U.S. Pat. No. 2,149,325, issued Mar. 7, 1939, to A. B. White; U.S. Pat. No. 2,158,368, issued May 16, 1939. to V. C. Hurt; U.S. Pat. No. 2,579,105, issued Dec. 18, 1951, to J. J. Baldine; and U.S. Pat. No. 2,946,134, issued July 26, 1960, to R. D. Neilson. A principal difficulty with these devices, however, is that their reduced size obviously prohibts the players from being on the field simultaneously with the teaching and analyzing devices.